Kai Ryssdal: A very simple guide to investing today, had we been able to go on the air at the opening bell, would've gone something like this: sell Greek government debt -- pretty much as fast as you can -- and buy Barnes & Noble.

We'll get to the bookstore in a minute, but the European debt crisis news today was all kinds of bad. There are reports the IMF wants even tougher austerity measures out of Athens. Fitch has downgraded Greek debt again. And the Norwegians, of all people, have stopped paying on a big aid grant to Athens. A simpler way of saying all of the above, I suppose, would've been to tell you there are fresh worries -- more fresh worries -- about a Greek debt default.

But on to the buy side of today's investment equation: Barnes & Noble. Liberty Media -- best known as the parent company of, among others, QVC, the home shopping network, and DirecTV, the satellite people -- has offered to buy the bookstore for $1 billion. That's a tidy sum for the one of the last big bookstore chains standing.

But Marketplace's Janet Babin reports Liberty's interest in the company isn't so much about the book business anyhow.

Brian Sozzi: Here's a company that was pretty much left for dead, where the model has just become outdated.

Marginalized by discounters online and in stores like Wal-Mart.

But Barnes & Noble has been busy since investors left it on the remainder table. It got its Nook e-reader to market in time for the electronic book craze. The company says it now has 25 percent of that market, making it a contender with Amazon and its Kindle.

The upgraded Nook Color has made gains too. IDC analyst Tom Mainelli says it can browse the web, stream video -- a lot of the same things that tablet devices, like the iPad, can do. All with one great advantage:

Mainelli: The iPad starts at $500 and the Nook Color, I think, is $250. So right there, you've got a much larger market.

A market Liberty Media could put to good use, and not just for books. The company's QVC shopping network could sell a lot of Snuggies and shiny baubles with those Nook Color tablets.

James McQuivey's an analyst at Forrester Research.

James McQuivey: Who knows, 20 million consumers who some day use the tablet or use the app on another tablet -- there's a QVC population ready to be sold to.

That's if Liberty Media's offer is successful. Shareholders may be heading out for a champagne toast tonight, but Barnes & Noble may skim through this offer, and hold out for an even bigger ending.